Hot water immersion induces an acute cytokine response in cervical spinal cord injury

Hot water immersion is associated with higher thermal comfort than dry passive heating for a similar rise in rectal temperature and plasma interleukin-6 concentration

PURPOSE

To compare the perceptual responses and interleukin-6 (IL-6) concentration following rectal temperature-matched dry heat exposure (DH) and hot water immersion (HWI).

METHODS

Twelve healthy young adults (BMI 23.5 ± 3.6 kg/m2; age: 25.8 ± 5.7 years) underwent 3 trials in randomised order: DH (air temperature 68.9 °C), HWI (water temperature 37.5 °C), and thermoneutral dry exposure (CON, air temperature 27.3 °C). Blood samples to determine IL-6 plasma concentration were collected; basic affect and thermal comfort, rectal and skin temperature (Tskin) were assessed throughout the intervention.

RESULTS

Rectal temperature (Trec) did not differ between DH (end temperature 38.0 ± 0.4 °C) and HWI (37.9 ± 0.2 °C, P = 0.16), but was higher compared with CON (37.0 ± 0.3 °C; P ≤ 0.004). Plasma IL-6 concentration was similar after DH (pre to post: 0.8 ± 0.5 to 1.4 ± 1.5 pg·ml-1) and HWI (0.5 ± 0.2 to 0.9 ± 0.6 pg·ml-1; P = 0.46), but higher compared with CON (0.6 ± 0.5 to 0.6 ± 0.4 pg·ml-1; P = 0.01). At the end of the intervention, basic affect and thermal comfort were most unfavourable during DH (Basic affect; DH: - 0.7 ± 2.9, HWI: 0.8 ± 1.9, CON 1.9 ± 1.9, P ≤ 0.004; Thermal comfort; 2.6 ± 0.8, HWI: 1.4 ± 0.9 and CON: 0.2 ± 0.4; P ≤ 0.004). Mean Tskin was highest for DH, followed by HWI, and lowest for CON (DH: 38.5 ± 1.3 °C, HWI: 36.2 ± 0.5 °C, CON: 31.6 ± 0.7 °C, P < 0.001).

CONCLUSION

The IL-6 response did not differ between DH and HWI when matched for the elevation in Trec. However, thermal comfort was lower during DH compared to HWI, which may be related to the higher Tskin during DH.

The effects of a single and a series of Finnish sauna sessions on the immune response and HSP-70 levels in trained and untrained men

BACKGROUND

The aim of the study was to investigate the effect of a Finnish sauna on the immune status parameters. The hypothesis was that hyperthermia would improve immune system's functioning by changing the proportion of lymphocyte subpopulations and would activate heat shock proteins. We assumed that the responses of trained and untrained subjects would be different.

MATERIAL AND METHODS

Healthy men (20-25 years old) were divided into groups: the trained (T; n = 10), and the untrained group (U; n = 10). All participants were subjected to 10 baths (each one consisted of: 3 × 15-minute exposure with cooled down for 2 min. Body composition, anthropometric measurements, VO₂ peak were measured before 1st sauna bath. Blood was collected before the 1st and 10th sauna bath, and 10 min after their completion to asses an acute and a chronic effect. Body mass, rectal temperature and heart rate (HR) were assessed in the same time points. The serum levels of cortisol, Il-6, HSP70 were measured with use of ELISA method, IgA, IgG and IgM by turbidimetry. White blood cells (WBC), leukocyte populations counts: neutrophils, lymphocytes, eosinophils, monocytes, and basophils were determined with use of flow cytometry as well as T-cell subpopulations.

RESULTS

No differences were found in the increase in rectal temperature, cortisol and immunoglobulins between groups. In response to the 1st sauna bath, a greater increase in HR was observed in the U group. After the last one, the HR value was lower in the T group. The impact of sauna baths on WBC, CD56+, CD3+, CD8+, IgA, IgG and IgM was different in trained and untrained subjects' responses. A positive correlation between the increase in cortisol concentrations and increase in internal temperatures after the 1st sauna was found in the T (r = 0.72) and U group (r = 0.77), between the increase in IL-6 and cortisol concentrations in the T group after the 1st treatment (r = 0.64), between the increase in IL-10 concentration and internal temperature (r = 0.75) and between the increase in IL-6 and IL-10 (r = 0.69) concentrations, also.

CONCLUSIONS

Sauna bathing can be a way to improve the immune response, but only when it is undertaken as a series of treatments.

Non-pharmacological interventions for vascular health and the role of the endothelium

The most common non-pharmacological intervention for both peripheral and cerebral vascular health is regular physical activity (e.g., exercise training), which improves function across a range of exercise intensities and modalities. Numerous non-exercising approaches have also been suggested to improved vascular function, including repeated ischemic preconditioning (IPC); heat therapy such as hot water bathing and sauna; and pneumatic compression. Chronic adaptive responses have been observed across a number of these approaches, yet the precise mechanisms that underlie these effects in humans are not fully understood. Acute increases in blood flow and circulating signalling factors that induce responses in endothelial function are likely to be key moderators driving these adaptations. While the impact on circulating factors and environmental mechanisms for adaptation may vary between approaches, in essence, they all centre around acutely elevating blood flow throughout the circulation and stimulating improved endothelium-dependent vascular function and ultimately vascular health. Here, we review our current understanding of the mechanisms driving endothelial adaptation to repeated exposure to elevated blood flow, and the interplay between this response and changes in circulating factors. In addition, we will consider the limitations in our current knowledge base and how these may be best addressed through the selection of more physiologically relevant experimental models and research. Ultimately, improving our understanding of the unique impact that non-pharmacological interventions have on the vasculature will allow us to develop superior strategies to tackle declining vascular function across the lifespan, prevent avoidable vascular-related disease, and alleviate dependency on drug-based interventions.

Local cooling during hot water immersion improves perceptions without inhibiting the acute interleukin-6 response

PURPOSE

Passive elevation of body temperature can induce an acute inflammatory response that has been proposed to be beneficial; however, it can be perceived as uncomfortable. Here, we investigate whether local cooling of the upper body during hot water immersion can improve perception without inhibiting the interleukin-6 (IL-6) response.

METHODS

Nine healthy male participants (age: 22 ± 1 years, body mass: 83.4 ± 9.4 kg) were immersed up to the waist for three 60-min water immersion conditions: 42 °C hot water immersion (HWI), 42 °C HWI with simultaneous upper-body cooling using a fan (FAN), and 36 °C thermoneutral water immersion (CON). Blood samples to determine IL-6 plasma concentration were collected pre- and post-water immersion; basic affect and thermal comfort were assessed throughout the intervention.

RESULTS

Plasma IL-6 concentration was higher for HWI and FAN when compared with CON (P < 0.01) and did not differ between HWI and FAN (P = 0.22; pre to post, HWI: 1.0 ± 0.6 to 1.5 ± 0.7 pg·ml^-1, FAN: 0.7 ± 0.5 to 1.1 ± 0.5 pg·ml^-1, CON: 0.5 ± 0.2 to 0.5 ± 0.2 pg·ml^-1). At the end of immersion, basic affect was lowest for HWI (HWI: - 1.8 ± 2.0, FAN: 0.2 ± 1.6, CON 1.0 ± 2.1, P < 0.02); thermal comfort for HWI was in the uncomfortable range (3.0 ± 1.0, P < 0.01 when compared with FAN and CON), whereas FAN (0.7 ± 0.7) and CON (-0.2 ± 0.7) were in the comfortable range.

CONCLUSION

Local cooling of the upper body during hot water immersion improves basic affect and thermal comfort without inhibiting the acute IL-6 response.

PATHOPHYSIOLOGICAL MECHANISMS OF BALNEOTHERAPY WITH POTENTIAL IMPLICATIONS FOR CENTRAL ASIAN SPAS AND SANATORIUMS

Spa therapy includes all modalities/ treatments based on evidence that are administered in spas or sanatoriums. Balneotherapy, the immersion in mineral water, is the main balneological modality in spa therapy programs. Clinical trials performed in Europe, Turkey, and Israel have shown clinical benefits of spa therapy/ balneotherapy in several diseases mainly pertaining to rheumatic and musculoskeletal diseases and dermatological diseases as well. However, mechanisms by which balneotherapy may improve the clinical symptoms of patients have been less evaluated/ documented in the literature. Although the literature on mechanisms of action of balneotherapy has still been evolving and accumulating, some evidence from preliminary studies paves the way for generating a hypothesis that balneotherapy has an influence on physiological mechanisms, immune system, inflammation, and oxidative stress. Extrapolation of the evidence-based clinical practice and scientific experience of Europe, Turkey, and Israel to Central Asian spas and sanatoriums is although possible; future studies investigating clinical efficacy, safety profile, and possible mechanisms of action of balneotherapy of regional spas are needed to better understand the role of balneotherapy and whether it has any local differences.

The effects of local versus systemic passive heating on the acute inflammatory, vascular and glycaemic response

The aim of this study was to compare the acute cardiometabolic and perceptual responses between local and whole-body passive heating. Using a water-perfused suit, 10 recreationally active males underwent three 90 min conditions: heating of the legs with upper-body cooling (LBH), whole-body heating (WBH) and exposure to a thermoneutral temperature (CON). Blood samples were collected before and up to 3 h post-session to assess inflammatory markers, while a 2 h oral glucose tolerance test was initiated 1 h post-session. Femoral artery blood flow and perceptual responses were recorded at regular intervals. The interleukin (IL)-6 incremental area under the curve (iAUC) was higher for LBH (1096 ± 851 pg/mL × 270 min) and WBH (833 ± 476 pg/mL × 270 min) compared with CON (565 ± 325 pg/mL × 270 min; p < 0.047). Glucose concentrations were higher after WBH compared with LBH and CON (p < 0.046). Femoral artery blood flow was higher at the end of WBH (1713 ± 409 mL/min) compared with LBH (943 ± 349 mL/min; p < 0.001), and higher in LBH than CON (661 ± 222 mL/min; p = 0.002). Affect and thermal comfort were more negative during WBH compared with LBH and CON (p < 0.010). In conclusion, local passive heating elevated blood flow and the IL-6 iAUC. However, while resulting in more positive perceptual responses, the majority of the included cardiometabolic markers were attenuated compared with WBH.

Novelty: The increase in the IL-6 iAUC in response to passive heating is not reduced by upper-body cooling. Upper-body cooling attenuates the plasma nitrite, IL-1ra and femoral artery blood flow response to passive heating. Upper-body cooling leads to more positive perceptual responses to passive heating.

Hot water immersion acutely increases postprandial glucose concentrations

Chronic hot water immersion (HWI) confers health benefits, including a reduction in fasting blood glucose concentration. Here we investigate acute glycemic control immediately after HWI. Ten participants (age: 25 ± 6 years, body mass: 84 ± 14 kg, height 1.85 ± 0.09 m) were immersed in water (39°C) to the neck (HWI) or sat at room temperature (CON) for 60 min. One hour afterward they underwent an oral glucose tolerance test (OGTT), with blood collected before and after HWI/CON and during the 2 h OGTT. Glucose incremental area under the curve (iAUC) during the OGTT was higher for HWI (HWI 233 ± 88, CON 156 ± 79 mmol·L^-1 ·2 h, P = 0.02). Insulin iAUC did not differ between conditions (HWI 4309 ± 3660, CON 3893 ± 3031 mU·L^-1 ·2 h, P = 0.32). Core temperature increased to 38.6 ± 0.2°C during HWI, but was similar between trials during the OGTT (HWI 37.0 ± 0.2, CON 36.9 ± 0.4°C, P = 0.34). Directly following HWI, plasma average adrenaline and growth hormone concentrations increased 2.7 and 10.7-fold, respectively (P < 0.001). Plasma glucagon-like peptide-1, peptide YY, and acylated ghrelin concentrations were not different between trials during the OGTT (P > 0.11). In conclusion, HWI increased postprandial glucose concentration to an OGTT, which was accompanied by acute elevations of stress hormones following HWI. The altered glycemic control appears to be unrelated to changes in gut hormones during the OGTT.

Impact of Finnish sauna bathing on circulating markers of inflammation in healthy middle-aged and older adults: A crossover study

OBJECTIVES

Finnish sauna bathing is associated with a reduced risk of adverse health outcomes. The acute physiological responses elicited by Finnish sauna bathing that could explain this association remain understudied. This study characterized the acute effect of Finnish sauna bathing on circulating markers of inflammation in healthy middle-aged and older adults.

DESIGN

With the use of a crossover study design, 20 healthy middle-aged and older adults (9 men/11 women, 66 ± 6 years old) performed 3 interventions in random order: 1) 1 x 10 min of Finnish sauna bathing (80 °C, 20 % humidity); 2) 2 x 10 min of Finnish sauna bathing; 3) a time-control period during which participants sat outside of the sauna for 10 min.

MAIN OUTCOMES

Venous blood samples were obtained before (≤15 min) and after (∼65 min) each intervention to determine circulating concentrations of interleukin 6 (IL-6), interleukin 1 receptor antagonist (IL-1RA), and C-reactive protein (CRP).

RESULTS

IL-6 increased in response to 2 x 10 min of sauna bathing (+0.92 pg/mL [+0.16, +1.68], P = 0.02), but not following the 1 x 10 min session (+0.17 pg/mL [-0.13, +0.47], P = 0.26). IL1-RA increased during the 1 x 10 min (+51.27 pg/mL [+20.89, +81.65], P < 0.01) and 2 x 10 min (+30.78 pg/mL [+3.44, +58.12], P = 0.03) sessions. CRP did not change in response to either sauna session (P = 0.34).

CONCLUSION

These results demonstrate that typical Finnish sauna bathing sessions acutely increase IL-6 and IL1-RA in healthy middle-aged and older adults.

The effect of temperature and heat shock protein 72 on the ex vivo acute inflammatory response in monocytes

The acute inflammatory response to active or passive activities that increase body temperature may aid to reduce chronic low-grade inflammation. This study investigates the impact of temperature and extracellular heat shock protein 72 (eHsp72) on the acute intracellular Hsp72 (iHsp72) and interleukin-6 (iIL-6) response in monocytes. Whole blood was incubated for 2 h at 37.0 °C, 38.5 °C and 40.0 °C, in the absence or presence of 0.5 μg/ml eHsp72. Flow cytometry was used to assess iHsp72 and iIL-6 expression in total monocytes and the three monocyte subsets. Incubation at 40.0 °C (p < 0.001) but not 38.5 °C (p = 0.085) increased iHsp72 expression when compared with 37.0 °C, while there was no effect of temperature on iIL-6 expression (p = 0.635). Following incubation with eHsp72, the expression of iHsp72 in classical monocytes was reduced at all temperatures (p < 0.001), while there was no effect of eHsp72 on iIL-6 expression (p = 0.071). Large temperature elevations are needed to induce an acute iHsp72 response in monocytes. In addition, contrary to its suggested role as a danger signal for the innate immune system, eHsp72 reduced iHsp72 and iIL-6 expression in monocytes.

Acute heat stress reduces biomarkers of endothelial activation but not macro- or microvascular dysfunction in cervical spinal cord injury

Cardiovascular diseases (CVD) are highly prevalent in spinal cord injury (SCI), and peripheral vascular dysfunction might be a contributing factor. Recent evidence demonstrates that exposure to heat stress can improve vascular function and reduce the risk of CVD in uninjured populations. We therefore aimed to examine the extent of vascular dysfunction in SCI and the acute effects of passive heating. Fifteen participants with cervical SCI and 15 uninjured control (CON) participants underwent ultrasound assessments of vascular function and venous blood sampling for biomarkers of endothelial activation (i.e., CD62e⁺) and apoptosis (i.e., CD31⁺/42b^-) before and after a 60-min exposure to lower limb hot water immersion (40°C). In SCI, macrovascular endothelial function was reduced in the brachial artery [SCI: 4.8 (3.2)% vs. CON: 7.6 (3.4)%, P = 0.04] but not the femoral artery [SCI: 3.7 (2.6)% vs. CON: 4.0 (2.1)%, P = 0.70]. Microvascular function, via reactive hyperemia, was ~40% lower in SCI versus CON in both the femoral and brachial arteries ( P < 0.01). Circulating concentrations of CD62e⁺ were elevated in SCI versus CON [SCI: 152 (106) microparticles/µl vs. CON: 58 (24) microparticles/µl, P < 0.05]. In response to heating, macrovascular and microvascular function remained unchanged, whereas increases (+83%) and decreases (-93%) in antegrade and retrograde shear rates, respectively, were associated with heat-induced reductions of CD62e⁺ concentrations in SCI to levels similar to CON ( P = 0.05). These data highlight the potential of acute heating to provide a safe and practical strategy to improve vascular function in SCI. The chronic effects of controlled heating warrant long-term testing. NEW & NOTEWORTHY Individuals with cervical level spinal cord injury exhibit selectively lower flow-mediated dilation in the brachial but not femoral artery, whereas peak reactive hyperemia was lower in both arteries compared with uninjured controls. After 60 min of lower limb hot water immersion, femoral artery blood flow and shear patterns were acutely improved in both groups. Elevated biomarkers of endothelial activation in the spinal cord injury group decreased with heating, but these biomarkers remained unchanged in controls.

Acute and chronic effects of hot water immersion on inflammation and metabolism in sedentary, overweight adults

Regular exercise-induced acute inflammatory responses are suggested to improve the inflammatory profile and insulin sensitivity. As body temperature elevations partly mediate this response, passive heating might be a viable tool to improve the inflammatory profile. This study investigated the acute and chronic effects of hot water immersion on inflammatory and metabolic markers. Ten sedentary, overweight men [body mass index (BMI): 31.0 ± 4.2 kg/m2, mean ± SD] were immersed in water set at 39°C for 1 h (HWI) or rested for 1 h at ambient temperature (AMB). Venous blood was obtained before the session, immediately postsession, and 2 h postsession for assessment of monocyte intracellular heat shock protein-72 (iHsp72) and plasma concentrations of extracellular Hsp72 (eHsp72), interleukin-6 (IL-6), fasting glucose, insulin, and nitrite. Thereafter, participants underwent a 2-wk intervention period, consisting of 10 hot water immersion sessions (INT). Eight BMI-matched participants (BMI: 30.0 ± 2.5 kg/m2) were included as control (CON). Plasma IL-6 and nitrite concentrations were higher immediately following HWI compared with AMB (IL-6 P < 0.001, HWI: 1.37 ± 0.94 to 2.51 ± 1.49 pg/ml; nitrite P = 0.04, HWI: 271 ± 52 to 391 ± 72 nM), whereas iHsp72 expression was unchanged ( P = 0.57). In contrast to resting iHsp72 expression ( P = 0.59), fasting glucose ( P = 0.04; INT: 4.44 ± 0.93 to 3.98 ± 0.98 mmol/l), insulin ( P = 0.04; INT: 68.1 ± 44.6 to 55.0 ± 29.9 pmol/l), and eHsp72 ( P = 0.03; INT: 17 ± 41% reduction) concentrations were lowered after INT compared with CON. HWI induced an acute inflammatory response and increased nitric oxide bioavailability. The reductions in fasting glucose and insulin concentrations following the chronic intervention suggest that hot water immersion may serve as a tool to improve glucose metabolism.

NEW & NOTEWORTHY A single hot water immersion (HWI) session induces an acute increase in plasma interleukin-6 and nitrite concentrations but does not acutely elevate heat shock protein-72 expression in monocytes [intracellular Hsp72 (iHsp72)]. A chronic HWI intervention reduces fasting glucose and insulin concentrations in the absence of changes in resting iHsp72. Therefore, HWI shows potential as a strategy to combat chronic low-grade inflammation and improve glucose metabolism in individuals without the physical capacity to do so using exercise.

Differences in serum IL-6 response after 1 °C rise in core body temperature in individuals with spinal cord injury and cervical spinal cord injury during local heat stress

OBJECTIVES

Passive rise in core body temperature achieved by head-out hot water immersion (HHWI) results in acute increases in serum interleukin (IL)-6 but no change in plasma adrenaline in patients with cervical spinal cord injury (CSCI). The purpose of the present study was to determine the mechanism of heat stress-induced increase in serum IL-6.

SETTING

A cross-sectional study.

METHODS

The study subjects were nine with CSCI, ten with thoracic and lumbar spinal cord injury (TLSCI) and eight able-bodied (AB) subjects. Time since injury was 16.1 ± 3.4 years in TLSCI and 16.4 ± 4.1 years in CSCI. Subjects were subjected to lower-body heat stress (LBH) by wearing a hot water-perfused suit until 1 °C increase in core temperature. The levels of serum IL-6, plasma adrenaline, tumour necrosis factor (TNF)-α, C-reactive protein (CRP), and counts of blood cells were measured at normothermia and after LBH.

RESULTS

Serum IL-6 concentrations increased significantly immediately after LBH in all the three groups. ΔIL-6% was lower in CSCI subjects compared with AB subjects. Plasma adrenaline concentrations significantly increased after LBH in AB and TLSCI subjects, but did not change throughout the study in CSCI subjects. Cardiac output and heart rate increased at the end of LBH in all three groups.

CONCLUSIONS

Under a similar increase in core temperature, ΔIL-6% was lower in the CSCI group compared with the AB group. These findings suggest that the observed rise in IL-6 during hyperthermia is mediated, at least in part, by plasma adrenaline.

Passive heat therapy protects against endothelial cell hypoxia-reoxygenation via effects of elevations in temperature and circulating factors

KEY POINTS

Accumulating evidence indicates that passive heat therapy (chronic use of hot tubs or saunas) has widespread physiological benefits, including enhanced resistance against novel stressors ('stress resistance'). Using a cell culture model to isolate the key stimuli that are likely to underlie physiological adaptation with heat therapy, we showed that both mild elevations in temperature (to 39°C) and exposure to serum from human subjects who have undergone 8 weeks of heat therapy (i.e. altered circulating factors) independently prevented oxidative and inflammatory stress associated with hypoxia-reoxygenation in cultured endothelial cells. Our results elucidate some of the mechanisms (i.e. direct effects of temperature vs. circulating factors) by which heat therapy seems to improve resistance against oxidative and inflammatory stress. Heat therapy may be a promising intervention for reducing cellular damage following ischaemic events, which has broad implications for patients with cardiovascular diseases and conditions characterized by 'chronic' ischaemia (e.g. peripheral artery disease, metabolic diseases, obesity).

ABSTRACT

Repeated exposure to passive heat stress ('heat therapy') has widespread physiological benefits, including cellular protection against novel stressors. Increased heat shock protein (HSP) expression and upregulation of circulating factors may impart this protection. We tested the isolated abilities of mild heat pretreatment and serum from human subjects (n = 10) who had undergone 8 weeks of heat therapy to protect against cellular stress following hypoxia-reoxygenation (H/R), a model of ischaemic cardiovascular events. Cultured human umbilical vein endothelial cells were incubated for 24 h at 37°C (control), 39°C (heat pretreatment) or 37°C with 10% serum collected before and after 8 weeks of passive heat therapy (four to five times per week to increase rectal temperature to ≥ 38.5°C for 60 min). Cells were then collected before and after incubation at 1% O₂ for 16 h (hypoxia; 37°C), followed by 20% O₂ for 4 h (reoxygenation; 37°C) and assessed for markers of cell stress. In control cells, H/R increased nuclear NF-κB p65 protein (i.e. activation) by 106 ± 38%, increased IL-6 release by 37 ± 8% and increased superoxide production by 272 ± 45%. Both heat pretreatment and exposure to heat therapy serum prevented H/R-induced NF-κB activation and attenuated superoxide production; by contrast, only exposure to serum attenuated IL-6 release. H/R also decreased cytoplasmic haemeoxygenase-1 (HO-1) protein (known to suppress NF-κB), in control cells (-25 ± 8%), whereas HO-1 protein increased following H/R in cells pretreated with heat or serum-exposed, providing a possible mechanism of protection against H/R. These data indicate heat therapy is capable of imparting resistance against inflammatory and oxidative stress via direct heat and humoral factors.

Increasing heat storage by wearing extra clothing during upper body exercise up-regulates heat shock protein 70 but does not modify the cytokine response

Plasma heat shock protein 70 (HSP70) concentrations rise during heat stress, which can independently induce cytokine production. Upper body exercise normally results in modest body temperature elevations. The aim of this study was to investigate the impacts of additional clothing on the body temperature, cytokine and HSP70 responses during this exercise modality. Thirteen males performed 45-min constant-load arm cranking at 63% maximum aerobic power (62 ± 7%V̇O_2peak) in either a non-permeable whole-body suit (intervention, INT) or shorts and T-shirt (control, CON). Exercise resulted in a significant increase of IL-6 and IL-1ra plasma concentrations (P < 0.001), with no difference between conditions (P > 0.19). The increase in HSP70 from pre to post was only significant for INT (0.12 ± 0.11ng∙mL^-1, P < 0.01 vs. 0.04 ± 0.18 ng∙mL^-1, P = 0.77). Immediately following exercise, T_core was elevated by 0.46 ± 0.29 (INT) and 0.37 ± 0.23ºC (CON), respectively (P < 0.01), with no difference between conditions (P = 0.16). The rise in mean T_skin (2.88 ± 0.50 and 0.30 ± 0.89ºC, respectively) and maximum heat storage (3.24 ± 1.08 and 1.20 ± 1.04 J∙g^-1, respectively) was higher during INT (P < 0.01). Despite large differences in heat storage between conditions, the HSP70 elevations during INT, even though significant, were very modest. Possibly, the T_core elevations were too low to induce a more pronounced HSP70 response to ultimately affect cytokine production.

Effect of spa therapy with saline balneotherapy on oxidant/antioxidant status in patients with rheumatoid arthritis: a single-blind randomized controlled trial

Oxidative stress has been shown to play a contributory role in the pathogenesis of rheumatoid arthritis (RA). Recent studies have provided evidence for antioxidant properties of spa therapy. The purpose of this study is to investigate whether spa therapy with saline balneotherapy has any influence on the oxidant/antioxidant status in patients with RA and to assess clinical effects of spa therapy. In this investigator-blind randomized controlled trial, we randomly assigned 50 patients in a 1:1 ratio to spa therapy plus standard drug treatment (spa group) or standard drug treatment alone (control group). Spa group followed a 2-week course of spa therapy regimen consisting of a total of 12 balneotherapy sessions in a thermal mineral water pool at 36-37 °C for 20 min every day except Sunday. All clinical and biochemical parameters were assessed at baseline and after spa therapy (2 weeks). The clinical parameters were pain intensity, patient global assessment, physician global assessment, Health Assessment Questionnaire disability index (HAQ-DI), Disease Activity Score for 28-joints based on erythrocyte sedimentation rate (DAS28-4[ESR]). Oxidative status parameters were malondialdehyde (MDA), nonenzymatic superoxide radical scavenger activity (NSSA), antioxidant potential (AOP), and superoxide dismutase (SOD). The NSSA levels were increased significantly in the spa group (p = 0.003) but not in the control group (p = 0.509); and there was a trend in favor of spa therapy for improvements in NSSA levels compared to control (p = 0.091). Significant clinical improvement was found in the spa group compared to the control in terms of patient global assessment (p = 0.011), physician global assessment (p = 0.043), function (HAQ-DI) (p = 0.037), disease activity (DAS28-4[ESR]) (0.044) and swollen joint count (0.009), and a trend toward improvement in pain scores (0.057). Spa therapy with saline balneotherapy exerts antioxidant effect in patients with RA as reflected by the increase in NSSA levels after spa therapy; whether this antioxidant effect contributes to the clinical improvements observed remains to be verified.